The trap of the present invention provides a more effective approach to attracting and capturing blood-sucking insects, particularly bed bugs. It combines a number of collection techniques with improved efficacy due to a synergistic combination of elements. It also reduces the amount of sprayed or broadcast chemicals that are used because ubiquitous non-toxic agents boost the effect of small amounts of chemicals.
The bed bug, cimex lectularius, is a small crawling blood-sucking insect that feeds on human, bird and bat blood. In the 1940s and 1950s, the widespread use of DDT and other residual pesticides caused a drastic decline in the bed bug population. However, bed bugs have developed resistances to these chemicals and are a rising threat to the commercial health of resort hotels, apartments, college dormitories, cruise ships and airplanes.
One approach to capturing insects has been the use of pitfall traps. The essential components of a pitfall trap are a container or pit and an interior wall that cannot be climbed. For example, a bug that falls into the trap will be unable to escape because it cannot climb up the interior wall, and is captured. Rough surfaces are easily climbed by bed bugs. Using their hook-like tarsal claws to engage fibres and surface roughness, bed bugs are capable of navigating vertical surfaces, for example, the underside of beds and even the human body. In fact, bed bugs exhibit behavior that seems to favor climbing inclined surfaces. In contrast, smooth surfaces can prove insurmountable and may even repel bed bugs. Smooth, hard surfaces can be made from glass, ceramics, metals, finished treatments on polished wood, finished treatments on paper, plastics and polymers. Insect and arthropod pitfall traps are known in the art, for example, U.S. Pat. No. 6,860,062 to Spragins discloses an adapted outdoor pitfall trap for crawling and flying insects; and U.S. Pat. No. 4,608,774 to Sherman discloses an indoor pitfall trap for cockroaches.
Another approach to capturing insects is the use of sensory lures. One such sensory lure is heat. Bed bugs are attracted to heat since heat can indicate a warm-blooded body. A temperature in the range of 43 to 45 degrees Celsius (109.4 to 113 degrees Fahrenheit) will attract bed bugs up to a distance of 25 mm at which point the bed bug will change path. Whereas a temperature of around 50 degrees Celsius (122 degrees Fahrenheit) will attract bed bugs to make direct contact with the heat source, and then be repelled after making contact. Insect and arthropod heat lures are known in the art, for example, U.S. Pat. No. 5,657,576 to Nicosia, U.S. Pat. No. 5,799,436 to Nolen, U.S. Pat. No. 6,055,766 to Nolen, U.S. Pat. No. 6,516,559 to Simchoni, and U.S. Pat. No. 7,117,632 to Lin each disclose the use of simulated human body heat to attract mosquitoes; U.S. Pat. No. 5,258,176 to Keenan discloses the use of heat to attract fleas and ticks; and published U.S. Patent Application No. 2007/0044372 to Lang discloses the use heat in the range of 26.6 to 37.7 degrees Celsius (80 to 100 degrees Fahrenheit) to attract bed bugs.
Another sensory lure is a chemical attractant. Bed bugs are attracted to chemical signals emitted by the hosts upon which they feed. Such chemical signals take the form of odor molecules, which drift away from the source by diffusion and by being carried in an air flow.
One chemical attractant is carbon dioxide, which is given off by respiring animals. Carbon dioxide is a ubiquitous gas in the atmosphere, with normal ambient background outdoor levels of 300 to 400 p.p.m. For example, normal adult human respiration expires around 200 ml/min of carbon dioxide, at a concentration of 45,000 p.p.m. in the expired air. Insects and arthropods that feed on host organisms are sometimes attracted to the increased carbon dioxide levels that are created by and thus surround the host. For example, tsetse flies and yellow fever mosquitoes are attracted by increased carbon dioxide levels over the ambient environment; blood-sucking conenose bugs are attracted by carbon dioxide levels between 300 and 400 p.p.m. over ambient levels; and mosquitoes are attracted linearly by carbon dioxide release rates up to 1,000 ml/min. Bed bugs are likewise attracted by carbon dioxide levels above ambient level.
Another chemical attractant detected by the olfactory senses of insects is an odor molecule such as L-lactic acid. L-lactic acid is a volatile component of human sweat that ranges in concentration from 0.5 to 5.0 mg/l. In some blood-sucking arthropods, L-lactic acid, when presented as a single stimulus, has only a slight or non-attractive effect. But when presented with carbon dioxide, L-lactic acid acts as a synergist and increases the attractiveness of the gas. The use of lactic acid as an attractant is known in the art, for example, U.S. Pat. No. 4,907,366 to Balfour discloses a trap for attracting mosquitoes using a composition consisting of lactic acid, carbon dioxide, water and heat.
Other chemical attractant odor molecules are the group of chemicals known as fatty acids, and, in particular, short chain fatty acids. Fatty acids are a volatile compound that include, but are not limited to, compounds such as acetic, propionic, isobutyric, butyric, isovaleric and valeric acids, all of which are present in human waste. The use of fatty acids as an attractant is known in the art, for example, Japan Patent No. JP-A-59062504 to Yasushi discloses an attractant composition for non-bloodsucking onion flies consisting of propionic acid, n-butyric acid, isobutyric acid, n-valeric acid, isovaleric acid, isocaprionic acid and 2-phenylethanol. See, also, U.S. Pat. No. 4,818,526 to Wilson and U.S. Pat. No. 5,258,176 to Keenan.
Another such attractant odor molecule is 1-Octen-3-ol (octenol). Octenol is a volatile component of cattle and human breath and sweat. Octenol is a potent olfactory attractant for tsetse flies and some mosquito species when combined with increased levels of carbon dioxide; for blood-sucking conenose bugs even at ambient carbon dioxide levels; and for mosquitoes, some of which are synergistically attracted by octenol and increased levels of carbon dioxide together. Others are attracted by octenol at ambient carbon dioxide levels. Bed bugs are attracted by octenol, but octenol is not an essential element in attracting bed bugs as evidenced by the fact that octenol is not emitted by birds, one of the other hosts of bed bugs. The use of carbon dioxide and/or octenol as an attractant of mosquitoes, no-see-ums, biting flies and ticks is known in the art from, for example, U.S. Pat. No. 5,205,064 to Nolen, U.S. Pat. No. 5,382,422 to Dieguez, U.S. Pat. No. 5,799,436 to Nolen, U.S. Pat. No. 6,055,766 to Nolen, U.S. Pat. No. 6,145,243 to Wigton, U.S. Pat. No. 6,199,316 to Coventry, U.S. Pat. No. 6,305,122 to Iwao, U.S. Pat. No. 6,516,559 to Simchoni, published U.S. Patent Application No. 2004/0025412 to Simchoni, U.S. Pat. No. 6,718,687 to Robison, U.S. Pat. No. 6,898,896 to McBride, U.S. Pat. No. 7,074,830 to Durand, U.S. Pat. No. 7,243,458 to Miller, U.S. Pat. No. 5,189,830 to Montemurro, and European Patent No. 1745697 to Geier.
Attractant chemical odor molecules can take on many forms and combinations. See, for example, European Patent No. WO 9826661 to Justus, U.S. Pat. No. 5,900,244 to Howes, U.S. Pat. No. 6,106,821 to Baker, U.S. Pat. No. 6,593,299 to Bennett, U.S. Pat. No. 6,800,279 to Bernier, U.S. Pat. No. 6,866,858 to Nolen, and U.S. Pat. No. 6,920,716 to Kollars.
Insect response to olfactory sensory neuron stimulation is dose dependent. For instance, the same compound may repel at one concentration and attract at another concentration.
The combination of highly effective chemical attractants with efficient traps allows for an improved control method to be developed. However, as is clear form the diversity of prior art, it is not possible to predict which compounds at which dosage levels will be effective attractants of a particular insect species. Accordingly, an effective trap for capturing bed bugs and the like, a lure composition for attracting bed bugs and the like, and a method for attracting and capturing bed bugs and the like is herein disclosed.